Systems using non-contact IC cards and non-contact IC tags have come into increased use in recent years. For example, non-contact data media which are provided with an IC inlet capable of electronic data input or the like are used in booklets such as passports and bank passbooks. A non-contact data medium has an integrated circuit (IC chip) and an antenna that is connected to the integrated circuit, with a base material that is superior in tear strength to high-quality paper or coated paper and also has good flexibility attached to both sides of the antenna sheet.
In general, the antenna of an antenna sheet, in addition to functioning as an antenna for data communication, functions as a coil to generate electrical power by electromagnetic induction for driving the integrated circuit. For this reason, in an antenna sheet a band-shaped antenna is wound in a coil-like (helical) shape on the surface of the antenna sheet. Given this constitution, the ends of the antenna are disposed at the inside and outside of the coil.
In order to connect the two ends of the antenna to the integrated circuit, it is necessary at least at one location to have a bridge between the inside and the outside of the antenna. In the usual antenna sheet, a conductive member (bridge pattern) is provided on the side of the sheet base material opposite from the side on which the antenna is formed, the inside and outside of the antenna being bridged by making a connection between the bridge pattern and the antenna end part and/or connection pattern.
In this type of connection part between the bridge pattern and the antenna, after forming the bridge pattern and antenna on both sides of the sheet base material, electrical conductivity is established therebetween by crimping both to make a mechanical contact therebetween (for example, Patent Document 1). Another known method of achieving electrical conductivity is to provide a through hole in the sheet base material and then either plate the inside of the hole or fill it with a conductive member.
Patent Document 1: Japanese Patent No. 3634774